Low refrigerant charge secondary heat exchange automobile thermal management system and control method thereof

Abstract

The invention relates to a secondary heat exchange automobile heat management system with low refrigerant charge and a control method of the secondary heat exchange automobile heat management system, and belongs to the field of electric automobile heat management. The system comprises a refrigerant loop and a cooling liquid loop, wherein the refrigerant loop comprises a compressor, a first refrigerant-cooling liquid heat exchanger, a second refrigerant-cooling liquid heat exchanger, an electronic expansion valve and a backheating gas-liquid separator which are connected through a refrigerant pipeline; the cooling liquid loop comprises first to fourth electronic water pumps, first and second refrigerant-cooling liquid heat exchangers, a warm air core body, a cold air core body, first and second controllable proportion three-way water valves, first to sixth three-way water valves, first and second four-way water valves, a heat dissipation water tank and an expansion kettle which are connected through a cooling liquid pipeline; the invention relates to a water heating positive temperature coefficient heater, a battery pack and a driving motor. The system aims at solving the problems that in a traditional heat pump system, the refrigerant charging amount is high, the leakage risk is large, and multifunctional heat management is complex, and the safety and the environment friendliness of the system are improved.

Description

Technical Field

[0001] The present invention relates to the field of electric vehicle thermal management, and particularly to a secondary heat exchange vehicle thermal management system with low refrigerant charge and its control method. Background Art

[0002] With the rapid development of the automotive industry and the increasingly strict environmental protection policies, the design of automotive thermal management systems is gradually shifting towards high efficiency, environmental protection, and energy conservation. As a technology that can flexibly switch between refrigeration and heating modes, heat pump technology has received extensive attention in the thermal management systems of electric vehicles. Currently, traditional heat pump systems mainly use direct evaporators and condensers as primary heat exchangers, and heat exchange is directly carried out between the refrigerant and the cockpit air. This structure has the following problems:

[0003] High refrigerant charge: In traditional systems, due to the need for large-capacity evaporators and condensers and long pipelines, the refrigerant charge is relatively high. Especially when using refrigerants with high global warming potential (GWP), it has a greater impact on the environment. In addition, reducing the charge is particularly crucial for the application of low-GWP refrigerants because these refrigerants are usually flammable, and a high charge increases the safety hazards of the system.

[0004] Risk of refrigerant leakage: In traditional designs, the refrigerant directly enters the cockpit air heat exchange process. Once the system leaks, the refrigerant may enter the vehicle, posing a threat to the safety and health of the occupants. For flammable refrigerants, this risk is even more significant, restricting their widespread application in vehicle heat pumps.

[0005] Insufficient utilization of the passenger compartment heat exchange core: In traditional systems, generally two heat exchange cores are provided in the passenger compartment. When both cores work simultaneously, they are used for defogging and defrosting conditions, and the refrigeration and heating conditions are achieved by a single core working, which results in low heat exchange efficiency of the core in the passenger compartment during refrigeration and heating conditions.

[0006] Complexity of multi-functional thermal management requirements: The automotive thermal management system not only needs to meet the refrigeration and heating requirements inside the vehicle but also needs to take into account multiple functions such as defogging, defrosting, battery cooling, and motor waste heat recovery. However, existing systems have deficiencies in function integration, often resulting in problems such as complex structure, low heat exchange efficiency, and high energy consumption. Summary of the Invention

[0007] Based on the above problems, the present invention proposes a new design of a thermal management system that can safely and efficiently achieve multi-functional thermal management on the premise of ensuring a low refrigerant charge.

[0008] The specific technical solutions are as follows:

[0009] Low refrigerant charge secondary heat exchange automotive thermal management system, including a refrigerant circuit and a coolant, which are independent of each other and exchange heat through a refrigerant-coolant heat exchanger;

[0010] The refrigerant circuit includes a compressor, a first refrigerant-coolant heat exchanger, an electronic expansion valve, a regenerative gas-liquid separator, and a second refrigerant-coolant heat exchanger connected by refrigerant pipes;

[0011] The coolant circuit includes a first electronic water pump, a second electronic water pump, a third electronic water pump, a fourth electronic water pump, a first refrigerant-coolant heat exchanger, a second refrigerant-coolant heat exchanger, a heater core, a cold air core, a first controllable proportional three-way water valve, a second controllable proportional three-way water valve, a first three-way water valve, a second three-way water valve, a third three-way water valve, a fourth three-way water valve, a fifth three-way water valve, a sixth three-way water valve, a first four-way water valve, a second four-way water valve, a radiator, an expansion water tank, a water-cooled positive temperature coefficient heater, a battery pack, and a drive motor (including a high-voltage end electronic control system) connected by coolant pipes;

[0012] The first end of the first refrigerant-coolant heat exchanger is connected to the compressor and the regenerative gas-liquid separator, the second end of the first refrigerant-coolant heat exchanger is connected to the electronic expansion valve, the third end of the first refrigerant-coolant heat exchanger is connected to the fourth three-way water valve and the sixth three-way water valve through the third electronic water pump, and the fourth end of the first refrigerant-coolant heat exchanger is connected to the heater core, the fourth three-way water valve, and the second controllable proportional three-way water valve through the third three-way water valve; The first end of the second refrigerant-coolant heat exchanger is connected to the regenerative gas-liquid separator, the second end of the second refrigerant-coolant heat exchanger is connected to the electronic expansion valve, the third end of the second refrigerant-coolant heat exchanger is connected to the first controllable proportional three-way water valve, the radiator, and the fifth three-way water valve through the first three-way water valve, and the fourth end of the second refrigerant-coolant heat exchanger is connected to the second four-way water valve, the fifth three-way water valve, and the sixth three-way water valve through the second electronic water pump.

[0013] The first end of the first four-way water valve is connected to the first three-way water valve, the second three-way water valve, and the second four-way water valve through a first variable ratio three-way water valve. The second end of the first four-way water valve is connected to the cold air core body. The third end of the first four-way water valve is connected to the warm air core body. The fourth end of the first four-way water valve is connected to the third three-way water valve, the warm air core body, and the third electronic water pump through a fourth three-way water valve. The first end of the second four-way water valve is connected to the first controllable ratio three-way water valve and the second three-way water valve. The second end of the second four-way water valve is connected to the second electronic water pump, the fifth three-way water valve, and the sixth three-way water valve. The third end of the second four-way water valve is connected to the first electronic water pump through a battery pack. The fourth end of the second four-way water valve is connected to the water-cooled positive temperature coefficient heater, the expansion water tank, the radiator, and the sixth three-way water valve, and is connected to the drive motor (including the high-voltage end electronic control system) through a fourth electronic water pump.

[0014] Preferably, the refrigerant provided in the refrigerant circuit is a refrigerant with low GWP and possible flammability (such as R290), and the coolant provided in the coolant circuit is a 50% ethylene glycol aqueous solution.

[0015] Preferably, a pressure and temperature sensor is provided on the refrigerant circuit, and a temperature sensor is provided on the coolant circuit for data acquisition.

[0016] Preferably, the connecting pipeline of the refrigerant circuit does not exceed 200 mm. The refrigerant circuit and the coolant circuit perform heat exchange through a refrigerant-coolant heat exchanger, reducing the large-capacity evaporator and condenser and the long pipeline, and greatly reducing the refrigerant filling amount.

[0017] Preferably, a regenerative gas-liquid separator is provided in the refrigerant circuit, integrating the functions of regeneration and gas-liquid separation, saving volume and refrigerant filling amount, and reducing throttling loss through regeneration.

[0018] Preferably, the refrigerant circuit and the coolant circuit constitute a secondary heat exchange system. The core body in the passenger compartment exchanges heat only through the coolant, and the refrigerant does not enter the passenger compartment, avoiding the threat to the safety and health of passengers caused by refrigerant leakage.

[0019] Preferably, the warm air core body and the cold air core body on the coolant circuit can be connected in series through a three-way water valve and a four-way water valve to enhance the heat exchange efficiency.

[0020] Preferably, a water-cooled positive temperature coefficient heater is provided on the coolant circuit, which can quickly restore the battery pack to the normal operating temperature under extremely low temperature conditions.

[0021] The present invention also provides a control method for a secondary heat exchange automotive thermal management system with low refrigerant charge, which can quickly respond to the mode requirements under different working conditions.

[0022] The advantages of the present invention are as follows:

[0023] (1) By adopting the design of the secondary heat exchange system, the thermal management system proposed by the present invention centralizes all the external heat exchange processes of the refrigerant in the refrigerant-coolant heat exchanger, realizing the optimization of the refrigerant circulation volume and greatly reducing the refrigerant charge. This not only reduces costs but also decreases the potential environmental impact of the refrigerant, meeting the environmental protection requirements under the background of carbon peaking and carbon neutrality.

[0024] (2) The thermal management system proposed by the present invention utilizes the secondary heat exchange technology to avoid the direct entry of the refrigerant into the cockpit, fundamentally eliminating the leakage and safety hazards that may be brought by flammable refrigerants.

[0025] (3) The thermal management system proposed by the present invention comprehensively considers the modes required under various working conditions, and realizes the cooling, heating, defogging, and defrosting of the passenger compartment, the heating and cooling of the battery pack in the power system, the cooling of the high-voltage end electronic control system, and the cooling and heat recovery of the drive motor by switching the flow direction of the coolant circuit through the valve body.

[0026] (4) The thermal management system proposed by the present invention connects the cold air core body and the warm air core body in the air conditioner box in series through the commutation function of the four-way water valve. Both heat exchange cores can exchange heat during refrigeration and heating, and the heat exchange is countercurrent relative to the air side, greatly increasing the efficiency of secondary heat exchange and solving the problem of poor secondary heat exchange performance.

[0027] (5) The thermal management system proposed by the present invention is designed to be compatible with a variety of refrigerants, which not only meets different market demands but also conforms to the trend of future environmental protection regulations.

[0028] (6) By dynamically adjusting the flow rate and temperature of the secondary circuit, the thermal management system proposed by the present invention realizes the adaptability to different environmental conditions, improving the stability and reliability of the system in extreme weather.

[0029] (7) The control method of the thermal management system proposed by the present invention realizes the automatic control of modes such as refrigeration, heating, defogging, defrosting, battery cooling, and motor waste heat recovery. Description of the Drawings

[0030] Figure 1 is the architecture diagram of the thermal management system of the present invention;

[0031] Figure 2 is the architecture decomposition diagram of the passenger compartment refrigeration mode system;

[0032] Figure 3It is the system architecture decomposition diagram of the battery cooling mode;

[0033] Figure 4 It is the system architecture decomposition diagram of the occupant compartment cooling + battery cooling mode;

[0034] Figure 5 It is the system architecture decomposition diagram of the occupant compartment heating + battery heating mode;

[0035] Figure 6 It is the system architecture decomposition diagram of the PTC-assisted occupant compartment heating + battery heating mode;

[0036] Figure 7 It is the system architecture decomposition diagram of the occupant compartment heating + battery heating + motor heat recovery mode;

[0037] Figure 8 It is the system architecture decomposition diagram of the front windshield heating + defrosting + defogging + battery heating mode;

[0038] Figure 9 It is the system architecture decomposition diagram of the front windshield defogging + occupant compartment cooling mode.

[0039] The meanings of the markings in the figure are as follows:

[0040] 101 - Compressor, 102 - First refrigerant-coolant heat exchanger, 103 - Electronic expansion valve, 104 - Second refrigerant-coolant heat exchanger, 105 - Regenerative gas-liquid separator, 201 - First three-way water valve, 202 - First controllable proportional three-way water valve, 203 - First four-way water valve, 204 - Cold air core, 205 - Second three-way water valve, 206 - Second four-way water valve, 207 - Battery pack, 208 - First electronic water pump, 209 - Water heating positive temperature coefficient heater, 210 - Second electronic water pump, 211 - Third three-way water valve, 212 - Warm air core, 213 - Fourth three-way water valve, 214 - Second controllable proportional three-way water valve, 215 - Fifth three-way water valve, 216 - Radiator, 217 - Sixth three-way water valve, 218 - Third electronic water pump, 219 - Fourth electronic water pump, 220 - Drive motor (including high-voltage end electronic control system), 221 - Expansion water tank. Specific implementation mode

[0041] As Figure 1 shown, the low-refrigerant charge secondary heat exchange vehicle thermal management system proposed in this implementation mode includes a heat pump system, namely a compressor 101, a first refrigerant-coolant heat exchanger 102, an electronic expansion valve 103, a second refrigerant-coolant heat exchanger 104, and a regenerative gas-liquid separator 105 connected through a refrigerant pipeline. The refrigerant set in the refrigerant circuit is a refrigerant with low GWP and possible flammability (such as R290);

[0042] The compressor 1 is used to compress the refrigerant to do work. The first refrigerant-coolant heat exchanger 102 and the second refrigerant-coolant heat exchanger 104 are used for heat exchange between the refrigerant and the coolant. The electronic expansion valve 103 is used to reduce the refrigerant flow area to achieve throttling and phase change. In this embodiment, without special explanation, the default mode of the electronic expansion valve is to reduce the refrigerant flow area. The regenerative gas-liquid separator 105 is used for heat exchange of the refrigerant in different states and has the function of separating the refrigerant returning from the evaporator to the compressor into gas and liquid. In this embodiment, a small-volume regenerative gas-liquid separator is adopted;

[0043] The coolant circuit includes a first three-way water valve 201, a first controllable proportional three-way water valve 202, a first four-way water valve 203, a cold air core 204, a second three-way water valve 205, a second four-way water valve 206, a battery pack 207, a first electronic water pump 208, a water-cooled positive temperature coefficient heater 209, a second electronic water pump 210, a third three-way water valve 211, a warm air core 212 and a fourth three-way water valve 213, a second controllable proportional three-way water valve 214, a fifth three-way water valve 215, a radiator 216, a sixth three-way water valve 217, a third electronic water pump 218, a fourth electronic water pump 219, a drive motor (including high-voltage end electronic control system) 220, and an expansion water tank 221, which are connected through coolant pipelines. The coolant set in the coolant circuit is a 50% ethylene glycol aqueous solution;

[0044] The first electronic water pump 208, the second electronic water pump 210, the third electronic water pump 218, and the fourth electronic water pump 219 are used to circulate the coolant in the system. The first controllable proportional three-way water valve 202 and the second controllable proportional three-way water valve 214 are used to adjust the distribution of the coolant flow rate. The first three-way water valve 201, the second three-way water valve 205, the third three-way water valve 211, the fourth three-way water valve 213, the fifth three-way water valve 215, the sixth three-way water valve 217, the first four-way water valve 203, and the second four-way water valve 206 are used to change the coolant flow direction. The cold air core 204 and the warm air core 212 are placed in the air-conditioning box in the cockpit and cooperate with the blower to provide the cold source or heat source for cooling and heating the passenger compartment. The water-cooled positive temperature coefficient heater 209 is used to heat the coolant circuit of the battery pack. The radiator 216 is placed in the front compartment and cooperates with the radiator fan to exchange heat with the coolant circuit by using the heat exchange between the coolant and the air. The expansion water tank 221 is used to supplement the coolant and stabilize the coolant pressure. The battery pack 207 needs to be cooled or heated to control its temperature within a certain range, and the drive motor (including high-voltage end electronic control system) 220 needs to be cooled;

[0045] Pressure and temperature sensors can be configured for each section of the pipeline in the heat pump system according to requirements, and temperature sensors can be configured for each section of the coolant circuit according to requirements, so as to detect the pressure or temperature of each section and perform automatic control through the feedback information.

[0046] The present invention can achieve different working modes by controlling the working states of various components. The following will introduce six working mode conversions of the secondary heat exchange vehicle thermal management system with low refrigerant charge under different typical working conditions. It should be noted that the described working mode principles are only part of the working conditions of the present invention, rather than all the working conditions. Other working conditions obtained by those of ordinary skill in the art based on the present invention without creative efforts should fall within the protection scope of the present invention.

[0047] Mode 1:

[0048] As Figure 2 shown, when the passenger compartment cooling mode is turned on, the specific working process and control method are as follows:

[0049] In the heat pump system, the compressor 101 is turned on. The rotational speed or power of the compressor can be adjusted according to requirements. At the same time, the opening degree of the electronic expansion valve 103 is controlled according to the feedback conditions of the sensor. The flow direction of the refrigerant is: compressor 101 - the first refrigerant - coolant heat exchanger 102 - the return gas - liquid separator 105 - the electronic expansion valve 103 - the second refrigerant - coolant heat exchanger 104 - the return gas - liquid separator 105 - the compressor 101. The first refrigerant - coolant heat exchanger 102 is used for heat dissipation of the heat pump system, and the second refrigerant - coolant heat exchanger 104 is used for refrigeration of the heat pump system.

[0050] In the coolant circuit, in this mode, the outdoor circuit is a high-temperature circuit (i.e., the heat dissipation circuit) for the heat management system to dissipate heat. When the third electric water pump 218 and the fourth electric water pump 219 are turned on, the lift of the electric water pump can be adjusted according to requirements, thereby controlling the flow rate of the coolant. When the 1-3 passage of the third three-way water valve 211 is opened, the second controllable proportional three-way water valve 214 can adjust the ratio of the 1-2 and 1-3 passages according to requirements, and this ratio can adjust the heat dissipation amount of the heat pump system and the drive motor (including the high-voltage end electronic control system) 220. When the 1-2 passage of the fifth three-way water valve 215 and the 1-2 passage of the sixth three-way water valve 217 are opened. The flow direction of the coolant is as follows: for the heat dissipation circuit of the heat pump system: the third electric water pump 218 - the first refrigerant-coolant heat exchanger 102 - the third three-way water valve 211 - the second controllable proportional three-way water valve 214 - the fifth three-way water valve 215 - the radiator tank 216 - the sixth three-way water valve 217 - the third electric water pump 218; for the heat dissipation circuit of the drive motor: the fourth electric water pump 219 - the drive motor (including the high-voltage end electronic control system) 220 - the second controllable proportional three-way water valve 214 - the fifth three-way water valve 215 - the radiator tank 216 - the fourth electric water pump 219. The heat transfer of the heat pump system is to first exchange heat with the coolant through the first refrigerant-coolant heat exchanger 102, and then exchange heat with the outside air through the radiator tank 216 to achieve the purpose of heat dissipation; the heat generated by the drive motor (including the high-voltage end electronic control system) 220 is carried out by the coolant, mixed with the coolant coming out of the heat pump system through the second controllable proportional three-way water valve 214, and enters the radiator tank 216 for heat dissipation.

[0051] In this mode, the indoor loop is a low-temperature loop (i.e., the refrigeration loop) for cooling the thermal management system. By turning on the second electronic water pump 210, the head of the water pump can be adjusted according to the demand, thereby controlling the flow rate of the coolant. By turning on the 1-2 passage of the first three-way water valve 201, the first controllable proportional three-way water valve 202 can adjust the ratio of the 1-2 and 1-3 passages according to the demand. This ratio can adjust the cooling capacity of the cockpit and the battery pack 207. In this mode, battery cooling is not turned on, so the opening ratio of the first controllable proportional three-way water valve 202 is 1-2:1-3 = 0:1, and the conduction state of the first four-way water valve 203 is 1-4, 2-3. Turn on the 1-3 passage of the fourth three-way water valve 213 and the 1-2 passage of the second three-way water valve 205. The conduction state of the second four-way water valve 206 is 1-2, 3-4. The flow direction of the coolant is: second electronic water pump 210 - second refrigerant-coolant heat exchanger 104 - first three-way water valve 201 - first controllable proportional three-way water valve 202 - first four-way water valve 203 - fourth three-way water valve 213 - first four-way water valve 203 - heater core 212 - first four-way water valve 203 - cold air core 204 - second three-way water valve 205 - second four-way water valve 206 - second electronic water pump 210. The cold produced by the heat pump system is transferred to the coolant through the second refrigerant-coolant heat exchanger 104, and then transferred to the heater core 212 and the cold air core 204 through the coolant. The heater core 212 and the cold air core 204 exchange heat with the air in the passenger compartment to achieve passenger compartment cooling.

[0052] Mode 2:

[0053] As Figure 3 shown, when the battery cooling mode is turned on, the specific working process and control method are as follows:

[0054] The working process of the heat pump system is the same as that in Mode 1 and will not be elaborated here.

[0055] In the coolant loop, the outdoor high-temperature loop is the same as that in Mode 1 and will not be elaborated here.

[0056] The indoor side circuit is a low-temperature circuit for cooling supply of the thermal management system. By turning on the second electronic water pump 210 and the first electronic water pump 208, the lift of the electronic water pump can be adjusted according to requirements, thereby controlling the flow rate of the coolant. By turning on the 1-2 circuit of the first three-way water valve 201, the first controllable proportional three-way water valve 202 can adjust the ratio of the 1-2 and 1-3 passages according to requirements. This ratio can adjust the cooling capacity of the cockpit and the battery pack 207. In this mode, only battery cooling is turned on, so the opening ratio of the first controllable proportional three-way water valve 202 is 1-2:1-3 = 1:0, and the conduction state of the first four-way water valve 203 is 1-4, 2-3. Turn on the 1-3 passage of the fourth three-way water valve 213 and the 1-2 passage of the second three-way water valve 205. The conduction state of the second four-way water valve 206 is 1-4, 2-3. The flow direction of the coolant is: the second electronic water pump 210—the second refrigerant-coolant heat exchanger 104—the first three-way water valve 201—the first controllable proportional three-way water valve 202—the second four-way water valve 206—the water-cooled positive temperature coefficient heater 209—the first electronic water pump 208—the battery pack 207—the second four-way water valve 206—the second electronic water pump 210. The cold produced by the heat pump system is transferred to the coolant through the second refrigerant-coolant heat exchanger 104, and then transferred to the battery pack 207 through the coolant to achieve battery cooling.

[0057] Mode Three:

[0058] As Figure 4 shown, when the occupant compartment cooling + battery cooling mode is turned on, the specific working process and control method are as follows:

[0059] The working process of the heat pump system is the same as that in Mode One and will not be elaborated here.

[0060] In the coolant circuit, the outdoor side high-temperature circuit is the same as that in Mode One and will not be elaborated here.

[0061] The indoor-side circuit is a low-temperature circuit for cooling in the thermal management system. By turning on the second electric water pump 210 and the first electric water pump 208, the head of the electric water pump can be adjusted according to requirements, thereby controlling the flow rate of the coolant. By turning on the 1-2 passage of the first three-way water valve 201, the first controllable proportional three-way water valve 202 can adjust the ratio of the 1-2 and 1-3 passages according to requirements, and this ratio can adjust the cooling capacity of the cockpit and the battery pack 207. The conduction state of the first four-way water valve 203 is 1-4, 2-3. By turning on the 1-3 passage of the fourth three-way water valve 213 and the 1-2 passage of the second three-way water valve 205, the conduction state of the second four-way water valve 206 is 1-4, 2-3. The flow direction of the coolant is: second electric water pump 210 - second refrigerant-coolant heat exchanger 104 - first three-way water valve 201 - first controllable proportional three-way water valve 202. Branch one (1-3 passage): first four-way water valve 203 - fourth three-way water valve 213 - heater core 212 - first four-way water valve 203 - cold air core 204 - second three-way water valve 205; Branch two (1-2 passage): directly conduct, - second four-way water valve 206 - water-cooled positive temperature coefficient heater 209 - first electric water pump 208 - battery pack 207 - second four-way water valve 206 - second electric water pump 210. The cold quantity produced by the heat pump system is transferred to the coolant through the second refrigerant-coolant heat exchanger 104, and then transferred to the heater core 212 and the cold air core 204 through the coolant. The heater core 212 and the cold air core 204 exchange heat with the air in the passenger compartment to achieve passenger compartment cooling, and the battery is cooled by transferring the coolant to the battery pack 207.

[0062] Mode Four:

[0063] As Figure 5 shown, when the passenger compartment heating + battery heating mode is turned on, the specific working process and control method are as follows:

[0064] The working process of the heat pump system is the same as that in Mode One and will not be elaborated here.

[0065] In this mode, the outdoor circuit is a low-temperature circuit (i.e., the heat absorption circuit), which is used for heat absorption of the thermal management system and heat dissipation of the drive motor. By turning on the second electronic water pump 210 and the fourth electronic water pump 219, the lift of the electronic water pump can be adjusted according to requirements, thereby controlling the flow rate of the coolant. Turn on the 1-3 passage of the first three-way water valve 201, the 1-3 passage of the fourth three-way water valve 213, and the 1-3 passage of the sixth three-way water valve 217. The second controllable proportional three-way water valve 214 can adjust the ratio of the 1-2 and 1-3 passages according to requirements. This ratio can adjust the heat dissipation of the heat pump system and the drive motor (including the high-voltage end electronic control system) 220. In this mode, the heat pump system does not require heat dissipation, so the opening ratio of the second controllable proportional three-way water valve 214 is 1-2:1-3 = 0:1, and turn on the 1-2 passage of the fifth three-way water valve 215. The flow direction of the coolant is as follows: for the heat absorption circuit of the heat pump system: the second electronic water pump 210 - the second refrigerant-coolant heat exchanger 104 - the first three-way water valve 201 - the radiator 216 - the sixth three-way water valve 217 - the second electronic water pump 210; for the heat dissipation circuit of the drive motor: the fourth electronic water pump 219 - the drive motor (including the high-voltage end electronic control system) 220 - the second controllable proportional three-way water valve 214 - the fifth three-way water valve 215 - the radiator 216 - the fourth electronic water pump 219. The heat transfer of the heat pump system is to first exchange heat with the coolant through the second refrigerant-coolant heat exchanger 104, and then exchange heat with the outside air through the radiator 216 to achieve the purpose of heat absorption; the heat generated by the drive motor (including the high-voltage end electronic control system) 220 is carried out by the coolant and enters the radiator 216 for heat dissipation. In this mode, the heat pump system will absorb part of the heat of the drive motor, which is beneficial to saving the energy consumption of the heat pump system and improving the system energy efficiency ratio.

[0066] In this mode, the indoor circuit is a high-temperature circuit (i.e., the heating circuit), which is used for heating of the thermal management system. By turning on the third electronic water pump 218, the lift of the electronic water pump can be adjusted according to requirements, thereby controlling the flow rate of the coolant. Turn on the 1-2 passage of the third three-way water valve 211, the conduction state of the first four-way water valve 203 is 1-4, 2-3, turn on the 1-3 passage of the second three-way water valve 205, and turn on the 1-2 passage of the fourth three-way water valve 213. The flow direction of the coolant is: the third electronic water pump 218 - the first refrigerant-coolant heat exchanger 102 - the third three-way water valve 211 - the heater core 212 - the first four-way water valve 203 - the cold air core 204 - the second three-way water valve 205 - the first four-way water valve 203 - the fourth three-way water valve 213 - the third electronic water pump 218. The heat generated by the heat pump system is transferred to the coolant through the first refrigerant-coolant heat exchanger 102, and then transferred to the heater core 212 and the cold air core 204 through the coolant. The heater core 212 and the cold air core 204 exchange heat with the air in the passenger compartment to achieve heating of the passenger compartment.

[0067] In this mode, the battery circuit is separated. The water-cooled positive temperature coefficient heater 209 heats the battery pack 207. The first electronic water pump 208 is turned on, and the lift of the electronic water pump can be adjusted according to requirements, thereby controlling the flow rate of the coolant. When the water-cooled positive temperature coefficient heater 209 is turned on, the conduction state of the second four-way water valve 206 is 1-2, 3-4. The direction of the coolant in this circuit is: the first electronic water pump 208 - the battery pack 207 - the second four-way water valve 206 - the water-cooled positive temperature coefficient heater 209 - the first electronic water pump 208. The water-cooled positive temperature coefficient heater 209 can convert electrical energy into heat energy to heat the battery pack 207.

[0068] Mode Five:

[0069] As Figure 6 shown, when the PTC auxiliary occupant compartment heating + battery heating mode is turned on, the specific working process and control method are as follows:

[0070] The working process of the heat pump system is the same as that in Mode One and will not be elaborated here.

[0071] In the coolant circuit, the indoor high-temperature circuit and the battery circuit are the same as those in Mode Four and will not be elaborated here.

[0072] The outdoor low-temperature circuit is used for heat absorption of the thermal management system (the heat comes from air and water heating PTC) and heat dissipation of the drive motor. When the first electronic water pump 208, the second electronic water pump 210, and the fourth electronic water pump 219 are turned on, the lift of the electronic water pump can be adjusted according to requirements, so as to control the flow rate of the coolant. When the 1-2 passage of the first three-way water valve 201 is turned on, the first controllable proportional three-way water valve 202 can adjust the ratio of the 1-2 and 1-3 passages according to requirements. In this mode, the opening ratio of the first controllable proportional three-way water valve 202 is 1-2:1-3 = 1:0, and the conduction state of the second four-way water valve 206 is 1-4, 2-3. When the water heating positive temperature coefficient heater 209 is turned on and all passages of the sixth three-way water valve 217 are closed, the second controllable proportional three-way water valve 214 can adjust the ratio of the 1-2 and 1-3 passages according to requirements. This ratio can adjust the heat dissipation of the heat pump system and the drive motor (including the high-voltage end electronic control system) 220. In this mode, the heat pump system does not need to dissipate heat, so the opening ratio of the second controllable proportional three-way water valve 214 is 1-2:1-3 = 0:1, and the 1-2 passage of the fifth three-way water valve 215 is turned on. The flow direction of the coolant is as follows: For the heat absorption circuit of the heat pump system: the second electronic water pump 210 - the second refrigerant-coolant heat exchanger 104 - the first three-way water valve 201 - the first controllable proportional three-way water valve 202 - the second four-way water valve 206 - the water heating positive temperature coefficient heater 209 - the battery pack 207 - the second four-way water valve 206 - the first electronic water pump 208 - the second electronic water pump 210; For the heat dissipation circuit of the drive motor: the fourth electronic water pump 219 - the drive motor (including the high-voltage end electronic control system) 220 - the second controllable proportional three-way water valve 214 - the fifth three-way water valve 215 - the radiator 216 - the fourth electronic water pump 219. The heat transfer of the heat pump system is to first exchange heat with the coolant through the second refrigerant-coolant heat exchanger 104, and then exchange heat through the water heating positive temperature coefficient heater 209 to achieve the purpose of heat absorption; the heat generated by the drive motor (including the high-voltage end electronic control system) 220 is taken out by the coolant and enters the radiator 216 for heat dissipation. In this mode, the battery pack 207 is heated, and the heat pump system absorbs the heat of the water heating positive temperature coefficient heater 209. In an extremely low-temperature environment, rapid heating of the passenger compartment can be achieved.

[0073] Mode Six:

[0074] As Figure 7 shown, when the passenger compartment heating + battery heating + motor heat recovery mode is turned on, the specific working process and control method are as follows:

[0075] The working process of the heat pump system is the same as that in Mode One and will not be elaborated here.

[0076] In the coolant circuit, the indoor high-temperature circuit and the battery circuit are the same as those in Mode Four and will not be elaborated here.

[0077] The outdoor low-temperature circuit is used for heat absorption of the thermal management system and heat dissipation of the drive motor. By turning on the second electronic water pump 210 and the fourth electronic water pump 219, the lift of the electronic water pump can be adjusted according to requirements, thereby controlling the flow rate of the coolant. Turn on the 1-3 passage of the first three-way water valve 201, the 1-3 passage of the fourth three-way water valve 213, and the 1-3 passage of the sixth three-way water valve 217. The second controllable proportional three-way water valve 214 can adjust the ratio of the 1-2 and 1-3 passages according to requirements. This ratio can adjust the heat dissipation of the heat pump system and the drive motor (including the high-voltage end electronic control system) 220. In this mode, the heat pump system does not need heat dissipation, so the opening ratio of the second controllable proportional three-way water valve 214 is 1-2:1-3 = 0:1, and turn on the 1-3 passage of the fifth three-way water valve 215. The flow direction of the coolant is as follows: For the heat absorption circuit of the heat pump system: the second electronic water pump 210 - the second refrigerant-coolant heat exchanger 104 - the first three-way water valve 201 - the radiator 216 - the sixth three-way water valve 217 - the second electronic water pump 210; For the heat dissipation circuit of the drive motor: the fourth electronic water pump 219 - the drive motor (including the high-voltage end electronic control system) 220 - the second controllable proportional three-way water valve 214 - the fifth three-way water valve 215 - the heat absorption circuit of the heat pump system - the fourth electronic water pump 219. The heat transfer of the heat pump system is to first exchange heat with the coolant through the second refrigerant-coolant heat exchanger 104, then exchange heat with the outside air through the radiator 216, and then mix with the coolant coming out of the drive motor (including the high-voltage end electronic control system) 220 to obtain all the heat generated by the motor (including the high-voltage end electronic control system) 220, achieving the purpose of heat absorption; the heat generated by the drive motor (including the high-voltage end electronic control system) 220 is carried out by the coolant and enters the heat pump system for heat dissipation. In this mode, the heat pump system will absorb all the heat of the drive motor, which is not only beneficial to saving the energy consumption of the heat pump system and improving the system energy efficiency ratio, but also can solve the problem that the heat pump cannot work properly under extremely low temperature conditions.

[0078] Mode Seven:

[0079] As Figure 8 shown, when the current gear defogging and defrosting + passenger compartment heating mode is turned on, the specific working process and control method are as follows:

[0080] The working process of the heat pump system is the same as that in Mode One and will not be elaborated here.

[0081] In the coolant circuit, the battery circuit is the same as that in Mode Four and will not be elaborated here.

[0082] In this mode, the outdoor side is only the cooling circuit for the drive motor. By turning on the fourth electronic water pump 219, the lift of the water pump can be adjusted according to requirements, thereby controlling the flow rate of the coolant. The second controllable proportional three-way water valve 214 can adjust the ratio of the 1-2 and 1-3 passages according to requirements. This ratio can adjust the heat dissipation of the heat pump system and the drive motor (including the high-voltage end electronic control system) 220. In this mode, the heat pump system does not require heat dissipation, so the opening ratio of the second controllable proportional three-way water valve 214 is 1-2:1-3 = 0:1. Turn on the 1-2 passage of the fifth three-way water valve 215 and close all passages of the sixth three-way water valve 217. Cooling circuit of the drive motor: Fourth electronic water pump 219 —— Drive motor (including high-voltage end electronic control system) 220 —— Second controllable proportional three-way water valve 214 —— Fifth three-way water valve 215 —— Radiator tank 216 —— Fourth electronic water pump 219.

[0083] In this mode, there are both a low-temperature circuit and a high-temperature circuit on the indoor side. In the high-temperature circuit, turn on the third electronic water pump 218, turn on the 1-2 passage of the third three-way water valve 211, the conduction state of the first four-way water valve 203 is 1-2, 3-4, turn on the 1-2 passage of the fourth three-way water valve 213, and the flow direction of the coolant is: Third electronic water pump 218 —— First refrigerant-coolant heat exchanger 102 —— Third three-way water valve 211 —— Heater core 212 —— First four-way water valve 203 —— Fourth three-way water valve 213 —— Third electronic water pump 218; In the low-temperature circuit, turn on the second electronic water pump 210, turn on the 1-2 passage of the first three-way water valve 201, and the first controllable proportional three-way water valve 202 can adjust the ratio of the 1-2 and 1-3 passages according to requirements. This ratio can adjust the cooling capacity of the cockpit and the battery pack 207. In this mode, only the occupant compartment is cooled, so the opening ratio of the first controllable proportional three-way water valve 202 is 1-2:1-3 = 0:1, the conduction state of the first four-way water valve 203 is 1-2, 3-4, turn on the 1-2 passage of the second three-way water valve 205, and the conduction state of the second four-way water valve 206 is 1-2, 3-4. The flow direction of the coolant is: Second electronic water pump 210 —— Second refrigerant-coolant heat exchanger 104 —— First three-way water valve 201 —— First controllable proportional three-way water valve 202 —— First four-way water valve 203 —— Cold air core 204 —— Second three-way water valve 205 —— Second four-way water valve 206 —— Second electronic water pump 210. The air in the occupant compartment enters the air-conditioning box and first exchanges heat with the cold air core 204. The water in the air condenses when cooled, and the condensed water is separated out, reducing the humidity in the air. Then it exchanges heat with the heater core 212, and the air is heated to blow out an appropriate temperature to defog and defrost the front windshield. In this mode, the cockpit is heated, and the theoretical heating capacity is the compressor power.

[0084] Mode Eight:

[0085] Such asFigure 9 As shown, when the front gear defogger + passenger compartment cooling mode is turned on, the specific workflow and control method are as follows:

[0086] The working process of the heat pump system is consistent with mode 1 and will not be repeated here.

[0087] In the coolant circuit, the outdoor high-temperature circuit is consistent with mode one and will not be described in detail; the indoor circuit is consistent with mode seven and will not be described in detail. The same thing is that the air in the passenger compartment enters the air conditioning box and first exchanges heat with the cold air core 204. The water in the air condenses when it is cold, and condensed water is precipitated, reducing the humidity in the air. Then, it exchanges heat with the warm air core 212, and the air is heated and blown out at a suitable temperature to defog the front windshield. At the same time, it ensures that the air outlet temperature of the air conditioning box will not be too low, affecting the comfort of the passengers. The difference is that in this mode, the heat pump system cools the passenger compartment, because the 1-2 and 1-3 paths of the third three-way water valve 211 are all connected, and heat is transferred to the outdoor air side through the heat dissipation water tank.

[0088] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A secondary heat exchange automotive thermal management system with low refrigerant charge, characterized in that, Comprising: A refrigerant circuit, which is formed into a closed cycle by sequentially connecting a compressor (101), a first refrigerant-coolant heat exchanger (102), an electronic expansion valve (103), a second refrigerant-coolant heat exchanger (104), and a regenerative gas-liquid separator (105) through pipelines; wherein: The outlet end of the compressor (101) is connected to the high-pressure side inlet of the first refrigerant-coolant heat exchanger (102); the high-pressure side outlet of the first refrigerant-coolant heat exchanger (102) is connected to the high-pressure side inlet of the regenerative gas-liquid separator, and the high-pressure side outlet of the regenerative gas-liquid separator (105) is connected to the low-pressure side inlet of the second refrigerant-coolant heat exchanger (104) through the electronic expansion valve (103); the low-pressure side outlet of the second refrigerant-coolant heat exchanger (104) is connected to the low-pressure side inlet of the regenerative gas-liquid separator (105), and the low-pressure side outlet of the regenerative gas-liquid separator (105) is connected to the inlet of the compressor (101); A coolant circuit, including a first branch and a second branch arranged in parallel. The first branch realizes refrigerant-coolant heat exchange through the first refrigerant-coolant heat exchanger (102), and the second branch realizes refrigerant-coolant heat exchange through the second refrigerant-coolant heat exchanger (104); the coolant circuit further includes: An occupant compartment temperature control module, which is composed of a cold air core body (204) and a warm air core body (212) connected in series, and the two form a double-core countercurrent heat exchange channel (relative to the air side) through a first four-way water valve (203); a battery thermal management module, including a battery pack (207), a second refrigerant-coolant heat exchanger (104), a radiator (216), and a water-cooled positive temperature coefficient heater (209); a drive motor (including a high-voltage side electronic control system) cooling module, including a radiator (216); A dynamic distribution network, which is composed of a first to sixth three-way water valve, a first to second controllable ratio three-way water valve, and a first to fourth electronic water pump, and is used to distribute coolant to the occupant compartment, battery, motor, and heat dissipation unit according to the mode requirements.

2. The secondary heat exchange automotive thermal management system with low refrigerant charge according to claim 1, wherein, The refrigerant in the refrigerant circuit is a refrigerant with a low global warming potential (GWP) and may have flammable, explosive properties (such as R290).

3. The secondary heat exchange automotive thermal management system with low refrigerant charge according to claim 1, characterized in that, The coolant in the coolant circuit is a 50% ethylene glycol aqueous solution.

4. A secondary heat exchange automotive thermal management system with low refrigerant charge according to claim 1, characterized in that A pressure sensor and a temperature sensor are provided on the refrigerant circuit, and a temperature sensor is provided on the coolant circuit for real-time monitoring of the system operation parameters.

5. A secondary heat exchange automotive thermal management system with low refrigerant charge according to claim 1, characterized in that, The connecting pipeline of the refrigerant circuit does not exceed 200 mm; a regenerator is provided inside the regenerative gas-liquid separator (105) to enable heat exchange between the low-pressure gas-phase refrigerant and the high-pressure liquid-phase refrigerant, and the subcooling degree before throttling is increased by ≥8°C, integrating the regenerative function and the gas-liquid separation function, which is used to reduce the throttling loss of the refrigerant and reduce the filling amount.

6. A secondary heat exchange automotive thermal management system with low refrigerant charge according to claim 1, characterized in that, The water-cooled positive temperature coefficient heater (209) in the coolant circuit is arranged in the battery thermal management module and is used to quickly heat the battery pack (207) under low-temperature conditions and provide part of the heat supply for the occupant compartment.

7. A secondary heat exchange automotive thermal management system with low refrigerant charge according to claim 1, characterized in that, In the refrigeration or heating mode, the coolant flows through the heater core (212) and the cold air core (204) in sequence, and forms a countercurrent heat exchange with the air in the air conditioning box.

8. A secondary heat exchange automotive thermal management system with low refrigerant charge according to claim 1, characterized in that, The multiple controllable proportional three-way water valves and the three-way water valve realize the switching of refrigeration, heating, defrosting, battery cooling and motor waste heat recovery modes by dynamically adjusting the coolant flow rate and flow direction.

9. A control method for a secondary heat exchange automotive thermal management system with low refrigerant charge as described in any one of claims 1-8, characterized in that, It includes the following steps: Select the system operation mode according to the ambient temperature, battery temperature and occupant compartment requirements; Control the heat exchange efficiency of the refrigerant circuit and the coolant circuit by adjusting the opening of the electronic expansion valve, the rotation speed of the electronic water pump and the distribution ratio of the controllable proportional three-way water valve; In the heating mode, the coolant is heated by outdoor air or the waste heat of the drive motor or the water heating positive temperature coefficient heater, and heat is supplied to the occupant compartment through the heater core and the cold air core; In the refrigeration mode, the secondary heat exchange efficiency is improved through the countercurrent heat exchange between the cold air core and the heater core and the air in the occupant compartment; In the battery cooling mode, the battery pack is cooled and temperature-controlled by the heat exchange between the refrigerant circuit and the coolant circuit and the distribution of the flow rate through the controllable proportional three-way water valve; In the defogging and defrosting mode, the four-way water valve is switched so that the high-temperature coolant flows through the heater core and the low-temperature coolant flows through the cold air core to defog and defrost the windshield and heat or cool the occupant compartment.

10. The control method of the secondary heat exchange automotive thermal management system with low refrigerant charge according to claim 9, characterized in that, When refrigerant leakage or abnormal system pressure is detected, the compressor is automatically shut down and switched to the safety mode, and the coolant circuit operates independently to meet the basic heat management requirements.

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